Andrew M. Cuomo, the governor of New York declared a state of emergency in Chemung County after a tornado reportedly touched down in Elmira, where author Mark Twain is buried. Most of the damage from yesterday's event occurred in New York and Pennsylvania where the weather front may have created a rare wind storm known as a derecho.

A derecho is defined as an event that has wind gusts of at least 58 miles per hour and leaves a swathe of damage for a minimum of 240 miles, according to the US Storm Prediction Centre.

At this point it is fair to say it is going to probably be a derecho, said Corey Mead, a meteorologist at the centre in Norman, Oklahoma. There is definitely going to be a continuous pattern of wind damage across New York, Pennsylvania and southern New England.

Clouds gather over apartment buildings ahead of a thunderstorm on the east side of Manhattan in New York (AFP/Getty Images)

Almost 386,000 customers were without power, including 4,000 in New York City, as of 8:30pm New York time yesterday after the storms had passed through the area, according to reports from utilities. At least 974 flights were cancelled around the US yesterday, with New York's LaGuardia Airport the hardest hit having 177 departures scrubbed, said FlightAware, a tracking company based in Houston.

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According to storm reports, winds of 75mph, strong enough to match a Category 1 hurricane, were recorded in Ohio and Kentucky. A gust of 74mph was recorded in Pennsylvania. Hail was reported from Arkansas to Pennsylvania, with the largest report so far being 2.5 inches in Montgomery, according to the storm centre.

Jessica Stansfield poses for a photo below an enormous uprooted tree after the town was hit by a tornado in Elmira, New York (Reuters)

Severe storms with lightning, hail and tornadoes accounted for about $8.8 billion in insured losses in the U.S. in the first six months of 2012, more than any other type of natural disaster, according to the Insurance Information Institute in New York.

The mid-Atlantic was struck by a derecho last month, leaving 4.3 million people without power from New Jersey to North Carolina as it unleashed winds of as much as 91mph. Twenty-four deaths were linked to the gale and its aftermath, according to The Associated Press.

Yesterday's storms were caused when a cold front swept across the US, Mead said. The most intense turbulence was in the Northeast, he said.

In New York's Chemung County, thousands of trees were shredded, businesses and homes were damaged and widespread power outages were reported, according to Cuomo. The state of emergency allows New York to waive rules that might hinder getting people there immediate help, a statement from the governor said.

Nearly 100,000 people in New York and about 145,000 in Pennsylvania were without electricity service, according to utility websites. New York City had about 4,000 people without power as storms rolled through, according to Consolidated Edison Inc.

FirstEnergy Corp., based in Akron, Ohio, said about 119,000 customers in Pennsylvania and 13,200 customers in Ohio had lost electricity by 8:30pm. American Electric Power Co., based in Columbus, Ohio, said more than 51,000 customers were blacked out, while NYSEG, a unit of Iberdrola SA, had about 52,000 without service in New York, according to the utilityÂ s website.

In West Virginia, 6,829 customers had lost their power as of 11pm, according to Appalachian PowerÂ s website. The company is owned by American Electric Power. An additional 603 customers were without electricity in Indiana, according to Duke Energy Corp.